Gut bacteria from obese humans made mice pack on fat, researchers reported Thursday in the latest finding showing the bugs in your tummy can affect weight.

Bacteria taken from thin people did not make mice fat, the researchers report in the journal Science.

In fact, bacteria from thin people appeared to protect mice from getting fat, perhaps by outcompeting “fat” germs.

They hope their findings will help eventually narrow down just which bacteria may affect how much energy people absorb from their food.

The hope is to eventually manufacture probiotics – pills, perhaps, or food — that can help people maintain a healthy weight.

Researchers have found that bacteria and fungi that live in and on our bodies affect health in many unexpected ways. They can prevent disease, cause dandruff, make feet stinky or sweet-smelling. And there’s a big growing body of evidence that the balance of bacteria in the intestines can affect how the body absorbs and uses energy from food.

And then they go on to talk about fecal implants and whatnot.

What I wonder is who lives longer: the fat gut-celled people or the skinny gut-celled people.